fix possible deadlock replacing processor state.

1 files changed, 6 insertions, 1 deletions

diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 5f98fba1fe..5a0959f8bb 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -2826,9 +2826,14 @@ Route::set_processor_state (const XMLNode& node)
 	}
 
 	{
-		Glib::Threads::Mutex::Lock lx (AudioEngine::instance()->process_lock ());
 		Glib::Threads::RWLock::WriterLock lm (_processor_lock);
+		/* re-assign _processors w/o process-lock.
+		 * if there's an IO-processor present in _processors but
+		 * not in new_order, it will be deleted and ~IO takes
+		 * a process lock.
+		 */
 		_processors = new_order;
+		Glib::Threads::Mutex::Lock lx (AudioEngine::instance()->process_lock ());
 
 		if (must_configure) {
 			configure_processors_unlocked (0, &lm);